Expandable osseointegration bone fixation apparatus for use in a variety of settings

ABSTRACT

“The embodiments disclosed provide an expandable osseointegration bone fixation apparatus configured to be attached to an affected or fractured bone. The apparatus includes an elongated housing containing a cylindrically shaped intraosseous insert have an expansion mechanism. The insert further includes a set of inwardly angled tapers designed to be attached to a diaphyseal bone where a set of diametrically opposed congruent inserts are configured to incrementally expanded in opposite directions and cause an incremental force against the inside surface of the housing to increase compression to the affected bone.”

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of provisional patent application No. 62/492,270 filed on Apr. 30, 2017 titled “Expandable Osseointegration Bone Fixation Device” by the present inventor.

FIELD

The present embodiment relates to a bone fixation apparatus, and, in particular, to an intramedullary fixation apparatus configured to be durably affixed to an affected bone and enable osseointegration within a plurality of microscopic pores.

BACKGROUND

It is often necessary in orthopedic surgery to affix a metal device into the patient's bone. Typically, surgery such as bone fracture repair uses bone screws to attach metal plates to the bone in order to restrict movement and to ensure the correct positioning of the bones being repaired. However, in other scenarios, the metal device is intended to permanently be incorporated into the patient's skeleton. A common situation is hip or knee joint replacement where the implant is intended to durably adhere to the patient's bones.

Some clinical scenarios, such as patients who have had multiple revision surgeries or bone tumor resections are challenging for current devices, in particular when there is a short segment of bone or only cortical bone is available. In these cases, current fixation technologies provide less than optimal long-term fixation.

Furthermore, currently available devices which are intended for fixation into cortical (shaft) bone require manual impaction of the device to produce pressure between the device and the host bone, which is challenging to reliably reproduce and thus introduces the potential for surgical error. Other devices use a spring-loaded mechanism to produce compression between metal and only the leading edge of the bone. Thus, the osseointegration surface is limited to a small area and so patients are prohibited from bearing weight for many weeks, and even then, the risk of early failure remains high.

This invention is intended to take advantage of the natural tendency of bone to grow into porous metallic surfaces and develop a durable attachment via “osseointegration”. This occurs when bone progenitor cells migrate into the metallic pores and form bone within and about the porous structure. This process is well known to allow for durable fixation of metal implants onto bone. Within the scope of the present invention, in each of the below embodiments, the porous and non-porous portions of the device may be coated with proteins from synthetic or animal source such as antibiotics, or include other coatings or radioactive materials to augment the therapeutic options of the invention.

SUMMARY OF THE INVENTION

Embodiments described herein include an expandable osseointegration bone fixation apparatus for use in a variety of settings including orthopedic, craniomaxillofacial and veterinary applications. The apparatus is configured to be affixed to a segment of bone and allow osseointegration with the affected bone segment. The apparatus is designed to be compressed against both the inside and the leading edge of an affected bone. The apparatus includes a housing containing an insert further comprised of two diametrically opposed congruent inserts. An expansion bolt at the centerline axis produces a sliding motion between the two inserts and leads to incremental transition between a first contracted and a second expanded position. The housing includes a first side opposite a second side whose diameters when added together are proportionate to the diameter of the affected bone. The housing is composed of a metallic material and designed to contain the insert having the two diametrically opposed congruent sections at a trailing end and a set of angled tapers at the leading end. The apparatus is compressed against the affected bone by twisting the expansion bolt causing horizontal expansion of the housing while simultaneously advancing the tapers further into the affected bone. Once inserted, a plurality of microscopic pores along the leading end of the housing and along the outer aspect of the tapers enable osseointegration between the bone and the several metallic surfaces of the apparatus.

In an alternative embodiment, the apparatus includes a plurality of grooves along the exterior walls of the housing portion outside the bone which enables incremental tightening of a threaded collar, causing compression between the collar and the leading edge of the bone, in addition to the interior of the bone.

In a further alternative embodiment, the apparatus includes a collar with a porous surface to slide toward to the affected bone without rotation. An adjustable nut is then applied opposite the sliding collar. When this nut is tightened, it causes increased pressure between the collar and bone, in addition to the pressure between the outside surface of the tapers and the affected bone.

In a further alternative embodiment intended for use near the ends of bones, the apparatus includes a transverse bolt designed to cause expansion of the inserts in a direction perpendicular to longitudinal axis of the bone and a plurality of screws inserted at the leading end of the insert to increase coronal compression of the apparatus against the leading edge of the bone.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1A is a perspective view of an expandable osseointegration bone fixation apparatus, with a tapered conical portion comprising the portion of the housing outside the bone, used to removably attach the apparatus to other metallic components;

FIG. 1B is a view of the apparatus sliding between the contracted and expanded positions;

FIG. 2A is an alternate view of the apparatus in an expanded position and further including a threaded collar for additional compression at the end of the bone;

FIG. 2B is the alternate view of apparatus with the threaded collar now compressed against the bone;

FIG. 3A is a further alternate embodiment of the apparatus with a threaded nut to be used to compress a collar against bone;

FIG. 3B is a further alternate embodiment now with threaded nut turned to compress collar against bone;

FIG. 4 is a further alternate embodiment of the apparatus intended for use near the end of a bone (metaphysis), demonstrating initial preparation of bone with router and guide;

FIG. 5A is the alternate embodiment of the apparatus inserted into the bone, fixed with screws into the bone, internal transverse bolt placed using removable jig; and

FIG. 5B is the alternate view of the apparatus now with the transverse bolt tightened, causing expansion of the device within the bone. 

What is claimed is:
 1. An expandable osseointegration bone fixation apparatus, comprising: an elongated and dimensioned housing having a first side equilaterally spaced and opposite to a second side and configured to be affixed at a leading end to an exterior surface of an affected bone and provide osseointegration with the affected bone; and an expandable insert configured to be in mechanical connection to a portion of the inside surface of the first and second sides of the elongated and dimensioned housing; the expandable insert having an expansion mechanism at a centerline axis to cause a set of diametrically opposed congruent inserts to incrementally expand in opposite directions and cause an incremental force against the inside surface of the housing when the expansion mechanism is transition from a first contracted position to a second expanded position and provide circumferential compression against the interior of the affected bone.
 2. The apparatus of claim 1, wherein the first and second sides of the housing enable lateral movement in a direction perpendicular to the expansion mechanism providing circumferential compression between the outside surface of the housing and the inside of the affected bone.
 3. The apparatus of claim 2, wherein the set of angled tapers is conical shaped and inwardly angled to provide opportunity of connection of the apparatus with other metallic components during surgery.
 4. The apparatus of claim 3, wherein an exterior surface of each of the set of angled tapers and a portion of the external housing coated with at a layer of proteins or other materials with therapeutic properties.
 5. The apparatus of claim 1, wherein the first and second sides of the elongated and dimensioned housing are comprised of a metallic material having a portion including a plurality of microscopic apertures to enable bone progenitor cells to migrate into the plurality of apertures and promote osseointegration.
 6. The apparatus of claim 1, wherein an apparatus width is defined by an inside diameter of the affected bone.
 7. The apparatus of claim 1, wherein the expansion mechanism includes a plurality of triangular shaped sleeves in mechanical communication and configured to provide longitudinal movement to the cylindrically shaped insert when an expansion bolt is rotated.
 8. The apparatus of claim 1, wherein the cylindrically shaped insert includes a threaded portion along the leading end to increase compression between the interior portion of the housing and the leading edge of the affected bone by allowing a threaded collar to be rotated into position or a separate nut to compress a sliding collar.
 9. The apparatus of claim 1, wherein the apparatus further includes at least one transverse bolt configured to be inserted in a perpendicular direction to the leading end of the apparatus to cause circumferential compression to the affected bone.
 10. The apparatus of claim 1, wherein the apparatus further includes a plurality of screws configured to be inserted with a plurality of apertures at the leading edge of the apparatus to create coronal compression with the affected bone.
 11. An expandable osseointegration bone fixation apparatus, comprising: an elongated and metallic housing having a first side opposite a second side and configured to be affixed within an affected bone and expand outward when a force from a contained insert is applied to an inside surface of the first side and the second side; a cylindrically shaped metallic insert dimensioned to fit inside the metallic housing and comprised of a set of diametrically opposed congruent inserts which transition from a first contracted to a second expanded position causing a compression between a set of angled tapers and the affected bone.
 12. The apparatus of claim 11, wherein a portion of an outside surface of the metallic housing includes a plurality of microscopic pores to allow progenitor cell migration within the plurality of microscopic pores and promote osseointegration.
 13. The apparatus of claim 11, wherein the insert further includes a threaded collar and nut at the leading end of the insert causing increased pressure between the affected bone and the inside surface of the set of angled tapers.
 14. The apparatus of claim 13, wherein the set of angled tapers further includes a plurality of microscopic pores.
 15. The apparatus of claim 11, further including a plurality of screws configured to be releasably attached within a plurality of slotted screw apertures along the leading end of the insert to enable coronal compression to the affected bone.
 16. The apparatus of claim 15, further including a transverse bolt inserted in a perpendicular direction to the longitudinal axis of the bone to provide axial compression between the metallic inserts and the interior of the affected bone.
 17. A metallic intramedullary bone fixation apparatus with a porous surface for use in a variety of setting to promote osseointegration, comprising: an elongated housing configured to fit within a diameter of an affected bone and having an first and second sides opposite to each other and further which move in a manner to expand within the bone and provide an outward force to the inside surface of the bone when the insert incrementally transitions from a first contracted position to a second expand position; and a metallic intramedullary bone fixation apparatus having a set of diametrically opposed congruent sections further including an expansion bolt along a centerline axis of the insert to provide for each section of the set of congruent sections to move in an opposite direction and increase compression to the affected bone. 